US and South Korea Launch Nuclear Cooperation Talks in Seoul

The Government of the United States and South Korea conducted a two-day inaugural security summit in Seoul from June 2 to June 3, 2026. Led by U.S. Under Secretary of State Allison Hooker and South Korean First Vice Foreign Minister Park Yoon-joo, the delegations sought to implement security initiatives established during an October 2025 summit between Presidents Donald Trump and Lee Jae Myung.

Negotiations focused on South Korea's goal to build conventionally armed, nuclear-propelled submarines, with a target launch date in the mid-2030s. The talks also addressed requests to revise the 2015 '123 Agreement' to grant South Korea advance consent for uranium enrichment and spent nuclear fuel reprocessing for civilian and commercial purposes. These measures aim to reduce Seoul's reliance on imported fuel and support its reactor exports.

The meetings followed several months of delays caused by U.S. focus on conflicts in Iran and the Middle East, as well as bilateral tensions regarding a data breach investigation at Coupang Inc. and legislative delays over a pledged $350 billion South Korean investment in the U.S. This investment is tied to an agreement for lower tariffs on Korean goods.

Both nations agreed to establish a progress-review mechanism and plan a follow-up round of consultations in Washington as early as July. The allies characterized the meetings as a return to track for security consultations intended to ensure peace and security in the Indo-Pacific region.